Looks like a magnesium deficiency. You don't have nearly enough bud action going for all the yellow fans to be normal. Something is out of balance.
As you are a month into flowering, we usually don't introduce nutes to the plants. That's because most organic nutes will leave a chemical taste in
your bud if you do not flush them before harvest.
If I was you I would flush your plants with a weak flowering nute. Those are pretty small pots so I assume you are watering every day? I would keep watering them daily with half-strength
nute water for 2 more weeks. Then flush again with pure water and continue with the daily watering with no nutes until harvest. I bet the yellow fans will
green up a bit. Most important -- healthy green leaves at this stage means your plants are also growing the buds you want. When one thing is out of whack,
like a chemical inbalance, plants will slow down or shut down other chores, like budding, until the problem is addressed.
Good luck, BigSteve.